Hold ctrl before selecting multiple elements with mouse
Adobe XD did this flawlessly, and to this day I can do designs from scratch faster in XD. This drives me crazy in Figma, and is the number one thing I hate about this platform. It constantly messes me up and I have to undo, manually select components, or zoom in.
In XD, the Frames (or Artboards) were always locked in place on the canvas, but could be moved by click dragging on the title of the artboard. The same implementation needs to be done here. You could move a Frame or Section by click dragging the title, otherwise they would remain in place.